Data Over Cable Service Interface Specification (DOCSIS) is a communication protocol used in cable networks to enable a headend cable mode termination system (CMTS), and customer premises equipment (CPE) including a cable modem (CM), to communicate with each other over the Internet and over a traditional cable plant. DOCSIS 3.1 uses orthogonal frequency division with multiple access (OFDMA) for upstream transmissions from the CM to the CMTS and orthogonal frequency division multiplex (OFDM) for downstream transmission from the CMTS to the CM where upstream and downstream channels are allocated differently in the RF communication spectrum. In OFDMA upstream transmission, a given CM looks for its time/frequency defined in a DOCSIS MAP that is sent from the CMTS to the CM to define the time/frequency of the CM's upstream transmission opportunities.
Recently, cable operators decided to increase the spectrum capacity to use the downstream channels for upstream transmission using a technique called Full Duplex DOCSIS. Full Duplex DOCSIS takes 3 downstream channels from the downstream spectrum and uses them for upstream channels if the CM (or a group of CMs) are not using the downstream channels. However, since a given CM may use one of the downstream channels as an upstream channel, the upstream channel may cause “noise” or “echo” that affects other downstream channels. A system and method is desired that enables the CM to measure such “noise” or “echo” effects in the upstream channel and offset these effects using echo cancellation techniques that minimize the adverse impact to adjacent downstream channels.